How do I determine the image size before creating the Buffer?

The `Content-Length` header in the HTTP response indicates the size of the image in bytes. Access this header using `response.headers['content-length']`. If the header is not present, you might need to download the entire image and then calculate its size, which is less efficient. Handle the case where `Content-Length` is missing gracefully, perhaps by downloading the entire image and then calculating its size.